We would attempt to isolate sulfobromophthalein binding peptide of subunit Ya of ligandin by limited proteolytic digestion of BSP-ligandin complex using V8 protease and separation of peptides by electrophoresis and chromatography. Distribution of steriod isomerase activity of ligandin on its subunits will be determined and inhibition of this enzyme activity by substrate of glutathione-S-transferase activity will be studied, in order to determine if steroid isomerase and glutathione transferase activities are located on same or different sites. High specific activity 3'methyl 4 dimethyl amino azo benzene has recently been acquired from New England Nuclear. A time dependent uptake, metabolism and binding of metabolites of this hepatocarcinogen to ligandin subunits and transport into nucleus would be studied in both hepatocytes maintained in cell culture as well as in whole animal. The carcinogen bound ligandin would be isolated from carcinogen fed rats and its catalytic, binding and immunological properties will be investigated. At present, the purity of our mRNA preparation for ligandin is 40-50%. This would be purified further by sucrose gradient centrifugation, gel electrophoresis and controlled hydridization. Single stranded cDNA will be prepared from the enriched fraction of ligandin mRNA. This cDNA will then be used as a probe for study of regulation of ligandin synthesis at the transcriptional level, during development, after phenobarbital administration and liver cell cancer.